Core catcher



J. HOFFOSS CORE CATCHER April 26, 1938.

Filed Jan. 2, 1937 Patented, Apr. 26, 1938 PATENT OFFICE 001m carcnun John Hofloss, Houston, Tex., assignor to Reed Roller Bit Company,

ration of Texas Houston, Tex., a coma- Application January 2, 1937, Serial No. 118,724

6 Claims.

This invention relates in general to core drills for use in taking samples of the formation during the drilling of a well or the like, and more particularly has reference to a device commonly known as a core catcher, which device is located adjacent the lower end of the barrel for receiving the core, and is for the purpose of breaking the core off, and for holding the core and preventingit from dropping out through the bottom of the core barrel during the time that the core barrel is being drawn up to the top of the well.

It is an object of this invention to provide a core catcher which shall be of simple construction and efficient in operation.

16 More specifically it is an object of this invention to provide a core catcher which will be less expensive to manufacture than previous core catchers, and which will be unfailing in its operation.

One other object of this invention is to provide a core catcher composed of a relatively small number of component parts requiring the least possible amount of labor to produce and assemble.

One other object of this invention is to provide a core catcher which may be used for breakin and retaining a core from practically any type of formation.

Another object of this invention is to provide a core catcher which will be extremely durable and require a minimum of repair and attention. Another object is to. provide a core catcher which when it requires repairs may be repaired with the least possible expenditure of labor and material.

One other object is to provide a core catcher which will present a smooth internal bore so as to permit the core to enter and pass freely therethrough. Other objects and advantages ofthis invention will become apparent from the following description taken in connection with the accompanying drawing, wherein one embodiment of this invention is illustrated. It is to be understood that stration is not by way' of limitation, but by w y of explanation and ilthis embodiment and lustration, and that this invention is limitedin its scope only by the prior art, and by the terms of the appended claims.

In the drawing:

Fig. 1 is a vertical cross sectional view illustrating a core catcher constructed in accordance with this invention, and showing its relation to' a core bit when in use therein.

Fig. 2 is a top plan view of the core catcher illustrated in Fig. 1.

Fig. 3 is a horizontal cross section of the core catcher only taken along the line 3-3 of Fig. l.

30 Fig. 4 is a vertical cross section of one side of the core catcher taken along the line 4-4 of The core barrel illustrated in Fig.1 is shown as being located within the lower end of the core barrel I and held in place therein by means of a shoulder in the lower portion of the core bit 2.

The principal part of the core catcher illustrated comprises the body 3 which is formed with a 'plurality of slots therein extending from' its lower end upwardly as illustrated at 4. Within these slots 4 there are disposed'core catcher fingers 5 and 6, these fingers being rotatively mounted upon a ring 1 of circular cross section which surrounds the lower end portion of the body 3 and snapped into place in a groove formed in the exterior of this body member.

A second ring-like member 8 of L-shaped cross section encloses the lower end of the body 3, and

is formed with slots extending from its upper edge downwardly corresponding in position to the slots 4 within the body member 3 and so arranged as to register with the slots 4. This member is likewise formed with an internal groove adapted to receive the outer portion of the ring I, and to retain this ring in position on the body member 3. The ring 8 is secured to the body member 3 by means of rivets 9 or the like.

Within the upper end portion of the core catcher body, this body is made of slightly enlarged diameter for the purpose of receiving the springmember ill in the form of a ring which exactly fits within the upper end portion'of the body 3. This spring ring I0 is preferably secured in position by means of spot welding H, or other suitable means.

Extending downwardly from the spring ring l0 in registering relation with a portion of the slots 4 are spring fingers l2, and other spring fingers 13 extend downwardly in registering position with respect to the remainder of the slots 4. The spring fingers [2 are so arranged as to contact the rear surfaces of the core catcher elements 6 and the spring fingers l3 likewise contact the rear surfaces of thecore catcher elements 5. These spring fingers it will be seen are, therefore, in

the path of the core as it moves upwardly into the core barrel.

The core catcher elements 5 and 6 are preferably of the type employed for catching and retaining cores cut from rock, shale, and other such position that they customarily urge the core catcher elements 5 and 6 toward the center of solid or substantially solid substances. Where it is proposed that the core catcher of this inven-' tion shall be usedfor soft formation cores, additional spring fingers will be provided extending upwardly from the ring shaped spring member it). These spring fingers will be curved toward the center of the path of a core entering the core barrel, and will themselves serve as core It will be understood from the foregoing that y in the course of taking the core with a core drill equipped with the core catcher described, the

core drill will be rotated in the ordinary manner to cut the core, and the core after it is cut will' pass upwardly between the core catcher elements I and 6 moving them to the position illustrated .in Fig. 1 against the tension of the spring fingers J2 and i3. After the core passes upwardly it will also come in contact with the inner surface 01 the spring fingers II, and will press them out- .wardly so that they will lie substantially flat end, and thereafter retain the core within the core barrel. The fingers I and 6 will, of course,

be'caused to move inwardly when the core bar-. rel is pulled up because of the tension of the spring fingers I: and it thereagainst, while the elements ll will move inwardly because of their own inherent tendency to assume the position illustrated in Fig. l.

' It is to be noted that in theoonstruction illustrated, there is provided a structure having a substantially smooth internal bore which will otter practically no resistance to the passage of a core therethrough in an upward direction. This is because the elements I and 8 are mounted within the slots 4, and when in their up position their inner surfaces are substantially flush with the inner wallsof the body member 3. In addition, the body member I is made of slightly larger diameter where it is to receive the spring.

member ID so that the inner surface .of this spring member ID forms a substantially smooth continuation of'the inner surface of the lower portion of the body member 3.

-It is further to be noted that there are a minimum number of parts involved in this construction, all of the spring members being formed in one piece, and all of the core catcher elements I and Q having a single member forming the' axis therefor. Moreover, the only securing operations required in assembling the dc?- vice are the steps of spot welding the spring member II in place, and of placing the rivets I in position. The device is thus capable of being assembled with the least amount of labor and expense.

, ,In addition to thecforegoing. it is tobe noted that if forinstance the spring member ill should become damaged and require replacement, it is only necessary to break loosethe spot welding I I, withdraw the damaged member, replacing it with a new member and spot welding the new memher in place. Also, if one of the elements 5 or 6 should become damaged and require replacement, it is only necessary to remove the rivets 9, slip the ring member 8' from the end of-the body member 3, and remove the damaged element, replacing it with a new one by a mere reversal of'this process.

- From the foregoing. it will be appreciated that a core catcher has been provided which is capable of carrying out all the objects and advan tages sought by this invention.

Having described my invention, I claim:

1. In a core catcher assembly, a ring-shaped body member having openings in the inner walls thereof, core catcher elements pivotally mounted within said openings to lie entirely therein when in their upper position, and swin'gable downwardly and inwardly from such position, and.a 10 single spring element having portions acting on said core catcher elements, respectively, and urging them toward such downward and inward position. I

2. In a core catcher assembly,.a ring-like bodypart, core catcher elements mounted therein for downward and inward swinging movement to re tain a core and a single spring element having a plurality of arms cooperating respectively with said core catcher elements and urging said core catcher elements downwardly and inwardly.

3. In a core catcher assembly, a ring-like body member having slots formed therein, a second ring-like member extending about 1 said body member adjacent said slots, a plurality of core catcher elements swingably mounted on said last mentioned'ring-like member and extending into said slots and adapted to swing downwardly and inwardly with respect to said body member, and means surrounding said body member and overso lying said second ring-like member to retain said second ring-hike member'in position on said body member, said secondring-like member interconnecting said ring-like 'body'and said last named meana.

4. In a core catcher assembly, a ring-hire body member having its upper portion of enlarged in-' ternal diameter, a plurality of core catcher elements mounted within said body -member for downward and inward swinging movement with '40 respect thereto, and a ring-like spring member fitted within the upper portion of enlarged diam eter on said body member and having parts engaging said core catcher elements and urging them to swing downwardly and inwardly with respect to the body member. a

5. Ina core catcher assembly, a ring-like body member, a plurality of core catcher elements mounted within said body member for downward and inward swinging movement with respect thereto, and a ring-:like'spring member mounted within said body member, and having parts cooperating with said core catcher'elementsto urge. the same downwardly and inwardly with respect to said. body member, said ring-like spring memher also having parts extending upwardly and inwardly therefrom and adapted to serve as core catcher, elements. g I

6. In a core catcher assembly, a ring-like body member, a second ring-like member extending m about said body member, a plurality of core catcher elements swingablymounted on said last mentioned ring-like member and adapted to swing downwardly and inwardly with respect to 

